U.S. patent number 8,920,511 [Application Number 13/680,222] was granted by the patent office on 2014-12-30 for multi-piece machine graft systems and methods.
This patent grant is currently assigned to AlloSource. The grantee listed for this patent is AlloSource. Invention is credited to Robert L. Bundy, Nate Henriod, Matthew Peterson, Matthew Southard.
View All Diagrams
United States Patent |
8,920,511 |
Southard , et al. |
December 30, 2014 |
Multi-piece machine graft systems and methods
Abstract
Embodiments of the present invention encompass graft assemblies,
and methods for their use and manufacture. An exemplary bone graft
assembly includes first and second bone pieces having respective
mating features which, when combined, define non-uniform press fit.
Related embodiments encompass graft assemblies having enclosed or
hidden mating features.
Inventors: |
Southard; Matthew (Englewood,
CO), Peterson; Matthew (Thornton, CO), Henriod; Nate
(Holladay, UT), Bundy; Robert L. (The Woodlands, TX) |
Applicant: |
Name |
City |
State |
Country |
Type |
AlloSource |
Centennial |
CO |
US |
|
|
Assignee: |
AlloSource (Centennial,
CO)
|
Family
ID: |
48430245 |
Appl.
No.: |
13/680,222 |
Filed: |
November 19, 2012 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20130211523 A1 |
Aug 15, 2013 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
61561002 |
Nov 17, 2011 |
|
|
|
|
61684218 |
Aug 17, 2012 |
|
|
|
|
Current U.S.
Class: |
623/23.51;
623/16.11 |
Current CPC
Class: |
A61F
2/28 (20130101); A61F 2/44 (20130101); A61F
2/4465 (20130101); A61F 2/4455 (20130101); A61F
2/30942 (20130101); A61F 2/30744 (20130101); A61F
2/4644 (20130101); A61F 2002/30138 (20130101); A61F
2002/30975 (20130101); A61F 2310/00023 (20130101); A61F
2250/006 (20130101); A61F 2/30965 (20130101); A61F
2002/30228 (20130101); A61F 2002/30329 (20130101); A61F
2002/30971 (20130101); Y10T 29/49826 (20150115); A61F
2002/30952 (20130101); A61F 2002/30154 (20130101); A61F
2/442 (20130101); A61F 2002/30062 (20130101); A61F
2310/00359 (20130101); A61F 2002/2817 (20130101); A61F
2002/2839 (20130101); A61F 2002/30604 (20130101); A61F
2002/30617 (20130101); A61F 2002/30126 (20130101); A61F
2002/30322 (20130101); A61F 2002/30057 (20130101); A61F
2002/30892 (20130101); A61F 2002/30785 (20130101); A61F
2002/30841 (20130101); A61F 2002/30897 (20130101); A61F
2002/2835 (20130101); A61F 2002/30448 (20130101); A61F
2002/30158 (20130101); A61F 2002/30332 (20130101); A61F
2002/30593 (20130101); A61F 2002/3055 (20130101); A61F
2/4611 (20130101); A61F 2002/30133 (20130101); A61F
2002/305 (20130101); A61F 2002/30487 (20130101); A61F
2002/30616 (20130101); A61F 2002/30151 (20130101); A61F
2002/30387 (20130101); A61F 2310/00017 (20130101); A61F
2002/30153 (20130101); A61F 2002/30383 (20130101); A61F
2002/30166 (20130101); A61F 2002/3082 (20130101); A61F
2002/30367 (20130101); A61F 2002/30787 (20130101); A61F
2002/30131 (20130101); A61F 2002/30354 (20130101); A61F
2002/30772 (20130101); A61F 2002/30112 (20130101); A61F
2002/30477 (20130101); A61F 2002/3079 (20130101); A61F
2002/30233 (20130101); A61F 2002/30327 (20130101); A61F
2002/30599 (20130101); A61F 2002/30782 (20130101); A61F
2002/30894 (20130101); A61F 2002/30733 (20130101); A61F
2/447 (20130101); A61F 2002/30115 (20130101); A61F
2002/30148 (20130101); A61F 2002/30324 (20130101); A61F
2002/30331 (20130101) |
Current International
Class: |
A61F
2/28 (20060101) |
Field of
Search: |
;623/16.11,23.5,23.51,23.52,23.63 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
International Search Report and Written Opinion of PCT/US2012/65832
mailed on Apr. 9, 2013, 19 pages. cited by applicant .
International Preliminary Report on Patentability for
PCT/US2012/065832, mailed on May 30, 2014; 2 pages. cited by
applicant.
|
Primary Examiner: Snow; Bruce E
Assistant Examiner: Dukert; Brian
Attorney, Agent or Firm: Kilpatrick Townsend & Stockton
LLP
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION
This application is a nonprovisional of, and claims the benefit of
U.S. Prov. Patent Application No. 61/561,002, filed Nov. 17, 2011
and U.S. Prov. Patent Application No. 61/684,218, filed Aug. 17,
2012, the entire disclosures of which are incorporated herein by
reference for all purposes.
Claims
What is claimed is:
1. A bone graft assembly, comprising: a first bone piece having a
peg mating feature, a recess mating feature, and a first aperture;
and a second bone piece having a peg mating feature, a recess
mating feature, and a second aperture, wherein the first bone piece
peg mating feature has a shape that is non complimentary to a shape
of the second bone piece recess mating feature and the second bone
piece peg mating feature has a shape that is non complimentary to a
shape of the first bone piece recess mating feature, such that when
the first and second bone pieces are coupled, an interface between
the first bone piece peg and the second bone piece recess mating
features is defined by a first non-uniform press fit and an
interface between the second bone piece peg and the first bone
piece recess mating features is defined by a second non-uniform
press fit, and wherein the first aperture is located in the first
bone piece and the second aperture is located in the second bone
piece such that when the first and second bone pieces are coupled,
the combination of the first and second apertures provide a passage
extending through the first and second bone pieces of the bone
graft assembly.
2. The bone graft assembly according to claim 1, wherein the peg
mating feature of the first bone piece comprises a polygon shape,
and the recess mating feature of the second bone piece comprises a
curved shape.
3. The bone graft assembly according to claim 2, wherein the
polygon shape comprises a member selected from the group consisting
of a regular polygon shape, an irregular polygon shape, an
equilateral polygon shape, and a cyclic polygon shape.
4. The bone graft assembly according to claim 1, wherein the peg
mating feature shape of the first bone piece comprises a corner
segment, and the recess mating feature shape of the second bone
piece comprises an arc segment, such that when the first and second
bone pieces are coupled, the corner and arc segments are pressed
together.
5. The bone graft assembly according to claim 4, wherein the corner
and arc segments both deform non-uniformly when the first and
second bone pieces are coupled.
6. A bone graft assembly, comprising: a first bone piece having a
peg mating feature, a recess mating feature, and a first aperture;
an intermediate bone piece construct having one or more bone
pieces, the intermediate bone piece construct providing a first peg
mating feature, a second peg mating feature, a first recess mating
feature, a second recess mating feature, and an intermediate
aperture; and a second bone piece having a peg mating feature, a
recess mating feature, and a second aperture, wherein the peg
mating feature of the first bone piece has a shape that is
non-complimentary to a shape of the first recess mating feature of
the intermediate bone piece construct, the recess mating feature of
the first bone piece has a shape that is non-complimentary to a
shape of the first peg mating feature of the intermediate bone
piece construct, the peg mating feature of the second bone piece
has a shape that is non-complimentary to a shape of the second
recess mating feature of the intermediate bone piece construct, and
the recess mating feature of the second bone piece has a shape that
is non-complimentary to a shape of the second peg mating feature of
the intermediate bone piece construct, such that when the first
bone piece and intermediate bone piece construct are coupled, an
interface between the first bone piece peg and intermediate bone
piece construct first recess mating features is defined by a first
non-uniform press-fit, an interface between the first bone piece
recess and intermediate bone piece construct first peg mating
features is defined by a second non-uniform press-fit, an interface
between the second bone piece peg and intermediate bone piece
construct second recess mating features is defined by a third
non-uniform press-fit, an interface between the second bone piece
recess and intermediate bone piece construct second peg mating
features is defined by a fourth non-uniform press-fit, and wherein
the first aperture is located in the first bone piece, the
intermediate aperture is located in the intermediate bone piece
construct, and the second aperture is located in the second bone
piece such that when the first and second bone pieces are coupled
with the intermediate bone piece construct the combination of the
first, intermediate, and second apertures provide a passage
extending through the first bone piece, the intermediate bone piece
construct, and the second bone piece construct of the bone graft
assembly.
7. The bone graft assembly according to claim 6, wherein the
intermediate bone piece construct includes a stack of at least two
bone pieces.
8. The bone graft assembly according to claim 6, wherein the
intermediate bone piece construct comprises a bone piece pair
having a first bone piece with a third peg mating feature and a
third recess mating feature and a second bone piece with a fourth
peg mating feature and a fourth recess mating feature, and wherein
the third peg mating feature of the first bone piece of the bone
piece pair has a shape that is non-complimentary to a shape of the
fourth recess mating feature of the second bone piece of the bone
piece pair, such that when the first and second bone pieces of the
bone piece pair are coupled, an interface between the third peg
mating feature of the first bone piece of the bone piece pair and
the fourth recess mating feature of the second bone piece of the
bone piece pair is defined by a fifth non-uniform press fit, and an
interface between the third recess mating feature of the first bone
piece of the bone piece pair and the fourth peg mating feature of
the second bone piece of the bone piece pair is defined by a sixth
non-uniform press fit.
9. The bone graft assembly according to claim 1, wherein the peg
mating feature of the first bone piece comprises one or more biting
edges that impinge against the recess mating feature of the second
bone piece.
10. The bone graft assembly according to claim 1, wherein the first
bone piece includes a second peg mating feature and a second recess
mating feature, the second bone piece includes a second peg mating
feature and a second recess mating feature, and wherein the second
peg mating feature of the first bone piece has a shape that is non
complimentary to a shape of the second recess mating feature of the
second bone piece and the second recess mating feature of the first
bone piece has a shape that is non complimentary to a shape of the
second peg mating feature of the second bone piece, such that when
the first and second bone pieces are coupled, an interface between
the second peg mating feature of the first bone piece and the
second recess mating feature of the second bone piece is defined by
a third non-uniform press fit and an interface between the second
recess mating feature of the first bone piece and the second peg
mating feature of the second bone piece is defined by a fourth
non-uniform press fit.
11. The bone graft assembly according to claim 10, wherein the
first and second peg mating features of the first bone piece have
equivalent dimensions.
12. The bone graft assembly according to claim 11, wherein the
first and second peg mating features of the second bone piece have
equivalent dimensions.
13. The bone graft assembly according to claim 10, wherein the
first and second recess mating features of the first bone piece
have equivalent dimensions.
14. The bone graft assembly according to claim 13, wherein the
first and second recess mating features of the second bone piece
have equivalent dimensions.
15. The bone graft assembly according to claim 10, wherein the
first and second peg mating features of the first bone piece and
the first and second peg mating features of the second bone piece
have equivalent dimensions, and wherein the first and second recess
mating features of the first bone piece and the first and second
recess mating features of the second bone piece have equivalent
dimensions.
16. The bone graft assembly according to claim 10, wherein the peg
mating feature and the second peg mating feature of the first bone
piece are located on opposing sides of the first bone piece
aperture.
17. The bone graft assembly according to claim 10, wherein the
recess mating feature and the second recess mating feature of the
first bone piece are located on opposing sides of the first bone
piece aperture.
18. The bone graft assembly according to claim 10, wherein the peg
mating feature and the second peg mating feature of the first bone
piece are located in a first plane, and are located on opposing
quadrants of the first bone piece diagonally from one another, and
wherein the recess mating feature and the second recess mating
feature of the first bone piece are located in a second plane, and
are located on opposing quadrants of the first bone piece
diagonally from one another, wherein the first plane is different
from the second plane, and wherein the peg mating feature opposing
quadrants are different from the recess feature opposing
quadrants.
19. The bone graft assembly according to claim 10, wherein the peg
mating feature and the second peg mating feature of the first bone
piece are located on opposing sides of the first bone piece
aperture, wherein the recess mating feature and the second recess
mating feature of the first bone piece are located on opposing
sides of the first bone piece aperture, wherein the peg mating
feature and the second peg mating feature of the second bone piece
are located on opposing sides of the second bone piece aperture,
wherein the recess mating feature and the second recess mating
feature of the second bone piece are located on opposing sides of
the second bone piece aperture, wherein the first and second peg
mating features of the first bone piece and the first and second
peg mating features of the second bone piece have equivalent
dimensions, and wherein the first and second recess mating features
of the first bone piece and the first and second recess mating
features of the second bone piece have equivalent dimensions.
20. The bone graft assembly according to claim 10, wherein the peg
mating feature and the second peg mating feature of the first bone
piece are disposed on a first surface of the first bone piece,
wherein the first bone piece comprises a third peg mating feature
and a fourth peg mating feature disposed on a second surface of the
first bone piece, and wherein the first surface of the first bone
piece is located opposite the second surface of the first bone
piece.
21. The bone graft assembly according to claim 20, wherein the
recess mating feature and the second recess of the first bone piece
are disposed on the first surface of the first bone piece, wherein
the recess mating feature and the third peg mating feature of the
first bone piece are in axial alignment, and wherein the second
recess mating feature and the fourth peg mating feature of the
first bone piece are in axial alignment.
22. The bone graft assembly according to claim 1, wherein the bone
graft assembly further comprises a plug configured for placement in
the passage, and wherein the plug comprises a cancellous bone
material.
23. The bone graft assembly according to claim 10, wherein the peg
mating feature and the second peg mating feature of the first bone
piece are hexagonal in shape, wherein the recess mating feature and
the second recess mating feature of the first bone piece are
circular in shape, wherein the peg mating feature and the second
peg mating feature of the second bone piece are hexagonal in shape,
and wherein the recess mating feature and the second recess mating
feature of the second bone piece are circular in shape.
Description
BACKGROUND OF THE INVENTION
Embodiments of the present invention are directed in general to the
field of medical grafts, and in particular to multi-piece graft
compositions, and methods of their use and manufacture.
Medical grafting procedures often involve the implantation of
autogenous, allograft, or synthetic grafts into a patient to treat
a particular condition or disease. The use of musculoskeletal
allograft tissue in reconstructive orthopedic procedures and other
medical procedures has markedly increased in recent years, and
millions of musculoskeletal allografts have been safely
transplanted. A common allograft is bone. Typically, bone grafts
are reabsorbed and replaced with the patient's natural bone upon
healing. Bone grafts can be used in a variety of indications,
including neurosurgical and orthopedic spine procedures for
example. In some instances, bone grafts can be used to fuse joints
or to repair broken bones.
Allograft and autogenous bone are both derived from humans; the
difference is that allograft is harvested from an individual (e.g.
donor) other than the one (e.g. patient) receiving the graft.
Allograft bone is often taken from cadavers that have donated their
bone so that it can be used for living people who are in need of
it, for example, patients whose bones have degenerated from cancer.
Such tissues represent a gift from the donor or the donor family to
enhance the quality of life for other people.
Hence, bone graft compositions and methods are presently available
and provide real benefits to patients in need thereof. Yet many
advances may still be made to provide improved bone graft systems
and methods for treating patients. The bone graft systems and
treatment and manufacture methods described herein provide further
solutions and answers to these outstanding needs.
BRIEF SUMMARY OF THE INVENTION
Embodiments of the present invention encompass multi-piece graft
compositions, and methods for their use and manufacture. For
example, bone grafts can be constructed of multiple bone pieces,
and can be used in a variety of clinical applications, including
without limitation, orthopedic, joint restoration, podiatry,
trauma, spine, oral maxillofacial, periodontal, and oncology
procedures. Exemplary bone graft configurations include spinal
grafts such as textured lordotic cervical spacers, parallel
cervical spacers, cortical cervical spacers, cortical/cancellous
cervical spacers, transforaminal lumbar interbody fusion (TLIF)
spacers, anterior lumbar interbody fusion (ALIF) spacers, posterior
lumbar interbody fusion (PLIF) spacers, laminoplasty implants or
devices, interspinous implants or devices, femoral rings, fibula
rings, radius rings, ulna rings, and any of a variety of wedges,
strips, dowels, struts, and the like.
In some instances, embodiments provide techniques for utilizing
donated bone or other tissue which is obtained in a variety of
sizes, structures, and consistencies. Embodiments also provide
effective approaches for producing larger grafts from smaller donor
pieces. Hence, use of the processes and products disclosed herein
can help to avoid the unwanted waste of donor tissue, while at the
same time providing quality, safe, bio-mechanically sound grafts
which enable surgeons and patients to achieve positive outcomes.
Accordingly, these techniques and systems may increase product
availability for allograft spinal orthopedic fusion material by
providing structural machined bone allografts, as well as other
types of machined grafts. Such grafts are particularly useful in
spinal fusion surgeries, and can provide structural support as well
as substrate for bone-bone fusion in the intervertebral disc
space.
Embodiments of the present invention also provide the ability to
join multiple graft pieces, including machine grafts, assembled
allografts, and the like, which may be constructed of or include
material such as cortical bone, cancellous bone, osteoconductive
material, or combinations thereof. In some cases, multi-piece
grafts or combined allografts can be manufactured by combining or
joining two or more male/female mating features. Graft pieces can
be joined, mated, or merged together, optionally without adhesives
(e.g. glue) and/or force driven mechanisms (i.e. clamps, vises,
screws, pins). This can be accomplished by combining unique
geometries with a light press or interference fit to create a
different (e.g. larger) machine graft within a particular graft's
existing monolithic configuration, function, shape, or quality.
The techniques described herein can be used with any of a variety
of graft tissues, including without limitation bone, tendon, and
the like. In some cases, multi-piece graft assemblies may include a
combination of different types of tissue. For example, a graft or
implant assembly may include a bone-tendon-bone (BTB)
configuration. In some cases, grafts or implants may also
incorporate or include other types of biological materials, such as
stem cells.
The present joining or uniting techniques can be used to construct
graft design which may otherwise be difficult to achieve due to
size constraints typically associated with single pieces of natural
donor bone or tissue. For example, the thickness of the cortical
wall in human bone, generally the long bones of the legs or arms,
rarely exceeds a certain threshold, which can limit the size of
grafts that can be produced as a single unit. Further, a large
fraction of donors are not suitable to make these kinds of grafts
in usable quantities because their bone thickness. Embodiments of
the present invention allow a much greater percentage of donor bone
to be used for creating grafts or implants.
According to some embodiments, grafts can be implanted within the
patient's body using specialized inserter materials, which may
include mating features designed to cooperate with corresponding
mating features on the graft itself. In certain surgical
procedures, the intervertebral space can be manipulated, for
example via distraction, and the graft inserted therein. In some
cases, a combination of plates and bone screws can be affixed to
adjacent vertebrae, and can at least partially cover the operative
space.
In one aspect, embodiments of the present invention encompass bone
graft assemblies, and systems and methods for their use and
manufacture. An exemplary bone graft assembly includes a first bone
piece having a first mating feature, and a second bone piece having
a second mating feature. The first mating feature has a shape that
is non-complimentary to a shape of the second mating feature, such
that when the first and second bone pieces are coupled, an
interface between the first and second mating features is defined
by a non-uniform press fit. In some cases, the first mating feature
has a polygon shape, and the second mating feature has e a curved
shape. In some cases, the polygon shape is a regular polygon shape,
an irregular polygon shape, an equilateral polygon shape, or a
cyclic polygon shape. In some cases, the first mating feature has
an irregular hexagon shape, and the second mating feature has a
racetrack shape. In some cases, curved shape can be an oval shape,
an ovoid shape, an elliptical shape, a slot shape, or a canal
shape. In some cases, the first mating feature has an inscribed
polygon shape, and the second mating feature has an inscribed
racetrack shape. In some cases, the first mating feature shape
includes a corner segment, and the second mating feature shape
includes an arc segment, such that when the first and second bone
pieces are coupled, the corner and arc segments are pressed
together. In some instances, corner and arc segments both deform
non-uniformly when the first and second bone pieces are
coupled.
In another aspect, embodiments of the present invention encompass
bone graft assemblies having a first bone piece with a first mating
feature, and a second bone piece with a second mating feature, and
the first and second mating features are configured to provide,
when approximated, a hidden engagement zone. In some cases, the
first mating feature includes a peripheral surface, a medial
surface, an inner surface, and a core surface, and the second
mating feature includes an outer surface, a peripheral surface, a
medial engagement surface, and an inner surface. In some cases, the
first and second mating features are configured to provide, when
approximated, a peripheral engagement zone defined between at least
portions of the peripheral surfaces of the first and second mating
features, respectively, a medial engagement zone defined between at
least portions of the medial surfaces of the first and second
mating features, respectively, and an inner engagement zone defined
between at least portions of the inner surfaces of the first and
second mating features, respectively. In some cases, the inner
engagement zone is disposed interior to the medial engagement zone.
In some cases, the medial engagement zone is disposed interior to
the peripheral engagement zone, and wherein at least a portion of
the medial engagement zone is disposed between the core surface of
the first mating feature and the outer surface of the second mating
feature. According to some embodiments, the first and second mating
features are configured to provide, when approximated, a continuous
aperture that extends through the first and second bone pieces of
the assembly. In some instances, the continuous aperture is at
least partially defined by the first and second mating features. In
some instances, the continuous aperture is not at least partially
defined by the first and second mating features. In some instances,
the first mating feature includes an annular wall disposed between
the first mating feature medial and core surfaces, and the second
mating feature includes a second annular wall disposed between the
second mating feature medial and outer surfaces. Optionally, the
second annular wall can be configured to slidingly receive the
first annular wall. In some instances, the first and second mating
features are configured to provide, when approximated, a press fit
at the medial engagement zone. According to certain embodiments, a
first mating feature medial surface is disposed interior to and
angularly offset from the first mating feature peripheral surface,
a first mating feature inner surface is disposed interior to and
angularly offset from the first mating feature medial surface, and
a first mating feature core surface is disposed interior to and
angularly offset from the first mating feature inner surface.
According to certain embodiments, a second mating feature
peripheral surface is disposed interior to and angularly offset
from the second mating feature outer surface, a second mating
feature medial surface is disposed interior to and angularly offset
from the second mating feature peripheral surface, and a second
mating feature inner surface is disposed interior to and angularly
offset from the second mating feature medial surface.
In yet another aspect, embodiments of the present invention
encompass methods of manufacturing or constructing a bone graft
assembly which include obtaining a first bone piece, processing the
first bone piece to produce a first mating feature thereon,
obtaining a second bone piece, and processing the second bone piece
to produce a second mating feature thereon. In certain embodiments,
the first mating feature has a shape that is non-complimentary to a
shape of the second mating feature, such that when the first and
second bone pieces are coupled, an interface between the first and
second mating features is defined by a non-uniform press fit. In
some instances, the processing of the first bone piece is performed
at least in part using a computer numerical control (CNC)
apparatus.
In still another aspect, embodiments of the present invention
encompass methods of manufacturing or constructing a bone graft
assembly which include obtaining a first bone piece, processing the
first bone piece to produce a first mating feature thereon,
obtaining a second bone piece, and processing the second bone piece
to produce a second mating feature thereon. In certain embodiments,
the first and second mating features are configured to provide,
when approximated, a hidden engagement zone. According to some
embodiments, the first mating feature includes a peripheral
surface, a medial surface, an inner surface, and a core surface.
According to some embodiments, the second mating feature includes
an outer surface, a peripheral surface, a medial engagement
surface, and an inner surface. According to some embodiments, the
first and second mating features are configured to provide, when
approximated, a peripheral engagement zone defined between at least
portions of the peripheral surfaces of the first and second mating
features, respectively, a medial engagement zone defined between at
least portions of the medial surfaces of the first and second
mating features, respectively, an inner engagement zone defined
between at least portions of the inner surfaces of the first and
second mating features, respectively, and a continuous aperture
that extends through the first and second bone pieces of the
assembly. According to some embodiments, the inner engagement zone
is disposed interior to the medial engagement zone. According to
some embodiments, the medial engagement zone is disposed interior
to the peripheral engagement zone, and at least a portion of the
medial engagement zone is disposed between the core surface of the
first mating feature and the outer surface of the second mating
feature. In some instances, the processing of the first bone piece
is performed at least in part using a computer numerical control
(CNC) apparatus.
In still another aspect, embodiments of the present invention
encompass methods of treating a patient with a bone graft assembly.
For example, a treatment method may include obtaining a bone graft
assembly, and administering the bone graft assembly to the patient.
In some cases, the bone graft assembly includes a first bone piece
having a first mating feature and a second bone piece having a
second mating feature. In certain embodiments, the first mating
feature has a shape that is non-complimentary to a shape of the
second mating feature, such that when the first and second bone
pieces are coupled, an interface between the first and second
mating features is defined by a non-uniform press fit. In some
cases, the bone graft assembly is positioned within the patient's
body using an introducer mechanism. In some cases, a portion of the
bone graft assembly may include a material such as titanium,
polyetherether ketone (PEEK), a steel-based alloy, metal, and
stainless steel. In some instances, a first bone piece and a second
bone pieced are bonded together with an adhesive. Optionally, the
adhesive may include a bone glue. In some instances, the bone graft
assembly is administered to a surgical site within or on the
patient's body. In some instances, the bone graft assembly is
administered to a site adjacent to a bone within the patient. In
some instances, the bone graft assembly is administered to a site
disposed between opposing bones within the patient. In some
instances, the bone graft assembly is administered to a site
disposed between opposing vertebrae within the patient. In certain
embodiments, the bone graft assembly includes an osteoconductive
material and/or an osteoinductive material. In some embodiments,
the bone graft assembly includes a stem cell composition. In some
instances, the stem cell composition is at least partially disposed
within an aperture of the bone graft assembly.
In still yet another aspect, embodiments of the present invention
encompass methods of treating a patient with a bone graft assembly,
which may include for example, obtaining a bone graft assembly, and
administering the bone graft assembly to the patient. In some
instances, the bone graft assembly includes a first bone piece
having a first mating feature, and a second bone piece having a
second mating feature, and the first and second mating features are
configured to provide, when approximated, a hidden engagement zone.
According to some embodiments, the first mating feature includes a
peripheral surface, a medial surface, an inner surface, and a core
surface, and the second mating feature includes an outer surface, a
peripheral surface, a medial engagement surface, and an inner
surface. In certain embodiments, the first and second mating
features are configured to provide, when approximated, a peripheral
engagement zone defined between at least portions of the peripheral
surfaces of the first and second mating features, respectively, a
medial engagement zone defined between at least portions of the
medial surfaces of the first and second mating features,
respectively, an inner engagement zone defined between at least
portions of the inner surfaces of the first and second mating
features, respectively, and a continuous aperture that extends
through the first and second bone pieces of the assembly. According
to certain embodiments, the inner engagement zone is disposed
interior to the medial engagement zone. According to certain
embodiments, the medial engagement zone is disposed interior to the
peripheral engagement zone, and at least a portion of the medial
engagement zone is disposed between the core surface of the first
mating feature and the outer surface of the second mating feature.
In some methods, the bone graft assembly is administered to a
surgical site within or on the patient's body. In some methods, the
bone graft assembly is administered to a site adjacent to a bone
within the patient. In some methods, the bone graft assembly is
administered to a site disposed between opposing bones within the
patient. In some methods, the bone graft assembly is administered
to a site disposed between opposing vertebrae within the
patient.
In another aspect, embodiments of the present invention encompass
bone graft assemblies which include a first bone piece, an
intermediate bone piece construct having one or more bone pieces,
and a second bone piece. In exemplary embodiments, a mating feature
of the first bone piece has a shape that is non-complimentary to a
shape of a first mating feature of the intermediate bone piece
construct, and a mating feature of the second bone piece has a
shape that is non-complimentary to a shape of a second mating
feature of the intermediate bone piece construct. In some
instances, the intermediate bone piece construct includes a stack
of at least two bone pieces. In some instances, the intermediate
bone piece construct includes a bone piece pair having a first bone
piece with a first mating feature and a second bone piece with a
second mating feature, and the first mating feature of the first
bone piece of the bone piece pair has a shape that is
non-complimentary to a shape of the second mating feature of the
second bone piece of the bone piece pair, such that when the first
and second bone pieces of the bone piece pair are coupled, an
interface between the first and second mating features of the first
and second bone pieces of the bone piece pair is defined by a
non-uniform press fit.
In still another aspect, embodiments of the present invention
encompass bone graft assemblies which include a first bone piece,
an intermediate bone piece construct having one or more bone
pieces, and a second bone piece. In certain embodiments, a mating
feature of the first bone piece and a first mating feature of the
intermediate bone piece construct are configured to provide, when
approximated, a first hidden engagement zone, and a mating feature
of the second bone piece and a second mating feature of the
intermediate bone piece construct are configured to provide, when
approximated, a second hidden engagement zone. In some instances,
the intermediate bone piece construct includes a stack of at least
two bone pieces. In some instances, the intermediate bone piece
construct includes a bone piece pair having a first bone piece with
a first mating feature and a second bone piece with a second mating
feature, and the first mating feature of first bone piece of the
bone piece pair and the second mating feature of the second bone
piece of the bone piece pair are configured to provide, when
approximated, a bone piece pair hidden engagement zone.
The above described and many other features and attendant
advantages of embodiments of the present invention will become
apparent and further understood by reference to the following
detailed description when considered in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1, 1A, and 1B depict aspects of bone graft assemblies, their
use, and/or manufacture, according to embodiments of the present
invention.
FIGS. 2A and 2B depict aspects of bone graft assemblies, their use,
and/or manufacture, according to embodiments of the present
invention.
FIG. 3 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 4 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIGS. 5A to 5D show aspects of bone graft assemblies, their use,
and/or manufacture, according to embodiments of the present
invention.
FIG. 6 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 7 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 8 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 9 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 10 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 11 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 12 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 13 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 14 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 15 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 16 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIGS. 17A and 17B illustrate aspects of bone graft assemblies,
their use, and/or manufacture, according to embodiments of the
present invention.
FIGS. 18A to 18D illustrate aspects of bone graft assemblies, their
use, and/or manufacture, according to embodiments of the present
invention.
FIG. 19 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 20 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 21 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 22 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 23 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 24 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 25 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIGS. 26 and 26A show aspects of bone graft assemblies, their use,
and/or manufacture, according to embodiments of the present
invention.
FIG. 27 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 28 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
FIG. 29 depicts aspects of bone graft assemblies, their use, and/or
manufacture, according to embodiments of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Bone material for use in grafting is typically produced by various
processes which may include debriding and removal of bone features
such as bone shaft ends. There is no constraint as to which bone is
actually used for a graft. In some instances, femurs and tibias are
particularly desirable candidates for producing grafts, in part
because these bones typically have a wall thickness that is greater
than what is found on other types of bones.
Bone grafts can be prepared using any of a variety of techniques.
For example, embodiments of the present invention include the
manufacture of bone grafts using computer numerical control (CNC)
machines, lathes, custom toolpaths and tooling, and the like. In
some instances, particular graft embodiments may involve the use of
custom cutters and/or jigs that are specifically designed for the
manufacturing process. Tooling can be designed to provide desired
production yields, speeds, and repeatability. This may involve
various factors such as tooling changes, removing and installing
new tooling or grafts, and set-up and tear down time.
In an exemplary manufacture process, a blank is cut from the bone,
providing an operator with a useable piece of donor material.
Often, such a piece is in the form of a square or block with a hole
therethrough, for example in the middle of the piece. The graft
piece can be cut or formed into its desired features using specific
tooling and jigs. Many grafts have cancellous in the middle which
serves as a bone growth stimulus. Osteoconductive or cancellous
material may be introduced into the graft at any desired stage of
the production process.
In some cases, techniques involve mechanically combining a multiple
number of smaller bone pieces to create a larger piece. Optionally,
such production processes may be accomplished without the use of
medical device parts such as metal screws, pins, or plates. In some
instances, production methods do not involve significant changes to
CNC machine or tooling configurations, provide enhanced usage of
donor tissue during processing and post processing, and provide
desirable processing speeds. In some cases, purified collagen,
calcium phosphate ceramics, or other osteoconductive materials may
be used in conjunction with multiple bone pieces when preparing or
implanting a bone graft assembly. In some cases, osteoinductive
materials may be used in conjunction with multiple bone pieces when
preparing or implanting a bone graft assembly. Exemplary
osteoconductive materials may include demineralized bone matrix,
stem cell products, and the like.
Turning now to the drawings, FIG. 1 illustrates aspects of a bone
processing technique according to embodiments of the present
invention. As shown here, a bone piece 100 (presented in both an
end view and a side view) obtained from a bone shaft presents an
outer profile or outer diameter (OD), an inner canal profile or
diameter (ID), and a wall thickness (WT). A graft piece or blank
110 can be obtained from bone piece 100 from graft location 120. In
some cases, the bone piece presents a cylindrical shape having a
wall thickness (WT) of at least 6 mm. In some cases, the bone piece
has a height (H) of at least 9 mm. Optionally, the bone piece may
have a height of at least 15 mm. Any of a variety of tissue types,
shapes, and sizes may be used to create a graft piece or blank.
Such graft pieces can be obtained or produced from any of a variety
of bone material types, including fresh bone, fresh-frozen bone,
freeze-dried bone, mineralized bone, demineralized bone, partially
demineralized bone, and the like. In some instances, bone pieces
can be obtained from any desired part of the skeleton, including
without limitation the humerus, talus, femur, tibia, fibula, rib,
pelvis, and the like.
Embodiments of the present invention encompass the use of multiple
graft pieces or blanks for the manufacture of multi-piece graft
compositions. In some instances, embodiments provide graft pieces
that are easy to assembly but difficult to disassemble. In some
cases, manufacturing methods involve the use of a minimal number of
graft pieces to produce a multi-piece graft composition. Exemplary
techniques also provide for the production of multi-piece grafts
having desirable biomechanical and aesthetic characteristics.
FIG. 1A illustrates an exemplary multi-piece bone graft assembly
100a according to embodiments of the present invention. Assembly
100a includes a first cortical (compact) bone piece 110a having a
first dovetail 112a mating feature, and a second cortical bone
piece 120a having a second dovetail 122a mating feature. Bone graft
assembly 100a also includes a first cancellous (spongy) bone pin
130a disposed within the first cortical bone piece, and a second
cancellous bone pin 140a disposed within the second cortical bone
piece. The dovetail features (112a, 122a) can provide a press fit
between the two pieces (110a, 120a). In some embodiments, the
assembly 100a can have a first dimension L of about 14 mm, a second
dimension D or about 10 mm, and a third dimension H or about 11 mm.
In certain embodiments, the mating features can have a dimension M
of about 1.59 mm. In certain embodiments, the pins may have a
dimension or diameter P of about 2.39 mm. These dimensions may be
varied or adjusted according to the use for which the assembly is
intended. For example, the dimensions can be adjusted for
appropriate use in a cervical spacer application, a vertebral
spacer application, and the like.
FIG. 1B illustrates an exemplary multi-piece bone graft assembly
100b according to embodiments of the present invention. Assembly
100b includes a first cortical bone piece 110b having a first
dovetail mating feature (female), a second cortical bone piece 120b
having a second dovetail mating feature (female), and a cancellous
bone piece 130b having two dovetail mating features (male) disposed
on opposing sides of the bone piece. The dovetail features can
provide a press fit between the three pieces. The particular
dimension values shown here (in millimeters) can be varied or
adjusted according to the use for which the assembly is intended.
For example, the dimensions can be adjusted for appropriate use in
a cervical spacer application, a vertebral spacer application, and
the like. In some cases, cancellous bone may be used for either or
both of the first and second pieces. In some cases, cortical bone
may be used for the third piece.
FIGS. 2A and 2B show aspects of an exemplary multi-piece bone graft
assembly 200 according to embodiments of the present invention.
Assembly 200 includes a first bone piece 210 having a first
dovetail mating feature 212 (socket), and a second bone piece 220
having a second dovetail mating feature 222 (fan). As shown here,
first bone piece 210 includes a depression or recess 230, and
second bone piece includes a raised boss or spot 240. When the
first and second bone pieces are combined, the dovetail features
engage in a press fit, and the first piece recess 230 receives the
second piece boss 240, so that the pieces snap and lock together.
In some cases, a bone piece may include both a male dovetail
feature (e.g. 213) and a female dovetail feature (e.g. 212), and in
this way multiple pieces can be combined in a stacked
configuration. Dovetail features can be configured in any of a
variety of angled configurations (e.g. 60 degree angle, as shown
here).
FIG. 3 illustrates an exemplary multi-piece bone graft assembly 300
according to embodiments of the present invention. Assembly 300
includes a first cortical bone piece 310 having a first dovetail
mating feature (socket), a second cortical bone piece 320 having a
second dovetail mating feature (socket), and a third bone piece 330
having two dovetail mating features (fans) disposed on opposing
sides of the piece. Bone graft assembly 300 also includes a bone
pin 340 disposed within the third bone piece. Third bone piece 330
may include cortical or cancellous bone, for example. Similarly,
bone pin 340 may also include cortical or cancellous bone. The
dovetail features can provide a press fit between the three pieces.
The pin may be configured as a plug, and optionally as a structural
supporting or non-structural non-supporting element. One or more
pieces of the assembly may include inserter slots configured for
use with an inserting instrument or device. Hence, the bone graft
assembly may be positioned within the patient's body using an
introducer mechanism 360. As depicted here, first bone piece 310
includes an inserter slot 312 and second bone piece 320 includes an
inserter slot 322. These slots can extend between the front side
and the back side of the bone pieces.
FIG. 4 illustrates an exemplary multi-piece bone graft assembly 400
according to embodiments of the present invention. Assembly 400
includes a first cortical bone piece 410 having a first dovetail
mating feature (female socket), a second cortical bone piece 420
having a second dovetail mating feature (female socket), and a
cancellous bone piece 430 having two dovetail mating features (male
fans) on opposing sides of the bone piece 430. The dovetail
features can provide a press fit between the three pieces. As shown
here, each of the pieces provide the graft assembly with surface
ridges or corrugations 401.
FIG. 5A illustrates an exemplary multi-piece bone graft assembly
500a according to embodiments of the present invention. Assembly
500a includes a first cortical bone piece 510a having a first
mating feature or boss 512a, a second cortical bone piece 520a
having a second mating feature or pocket 522a, and a cancellous pin
or plug 530a that can be inserted through both the first and second
cortical bone pieces via respective apertures (540a, 550a) in the
first and second bone pieces. As shown here, the first and second
bone pieces engage in such a way that the mating features are
enclosed or hidden from view when the bone pieces are combined.
This configuration provides a large amount of surface area for
mating. Further, the pieces can be constructed without removing a
significant amount of graft material from a donor bone. In some
cases, the bone pieces can be constructed with a line to line
tolerance. In some instances, first and/or second bone pieces may
not each have an aperture therethrough. In some embodiments,
purified collagen, calcium phosphate ceramics, or other
osteoconductive materials may be placed within apertures or holes
of the bone pieces. This approach can be used to stack any desired
number of bone pieces together. One or more surface of the bone
pieces may include ridges or corrugations (e.g. 511a). The
dimensions depicted here (in millimeters) may be varied or adjusted
according to the use for which the assembly is intended. For
example, the dimensions can be adjusted for appropriate use in a
cervical spacer application, a vertebral spacer application, and
the like.
Hence, as depicted here, two graft pieces can be joined together
using a male boss or ridge (512a) and a female hole or recess
522a), thus providing an interference or press fit. Both male and
female features can have the same contour shape as its mating
counterpart. In some cases, a size differential between the
components can create interference which resists separation. In
some instances, such graft pieces can be joined together using a
male boss and a female pocket interference or press fit, such that
both male and female features have the same contour shape as its
mating counterpart, and the combined graft assembly presents an
outside profile of a cervical graft shape. A size differential
between the components or mating features can create an
interference that resists separation.
A cervical spacer bone graft assembly having features similar to
those of FIG. 5A was tested in comparison with a monolithic spacer.
The observed Compression Averages (N) for a monolithic structure
and bone graft (multi-piece) assembly were 15,000 and 13,200,
respectively. Hence, the multi-piece features of the bone graft
assembly were not observed to have a significant effect on
compression properties as compared to a monolithic structure.
Moreover, as explained in Patwardhan et al., Load-carrying capacity
of the human cervical spine in compression is increased under a
follower load, Spine 2000 Jun. 15; 25(12):1548-54, the content of
which is incorporated herein by reference, the compressive load on
the human cervical spine is estimated to range from 120 to 1200 N
during activities of daily living. Hence, the tested graft assembly
provides more than sufficient load strength for an implant.
FIG. 5B illustrates an exemplary multi-piece bone graft assembly
500b according to embodiments of the present invention. Assembly
500b includes a first cortical bone piece 510b having a first
mating feature or boss 512b, a second cortical bone piece 520b
having a second mating feature or pocket 522b, and a cancellous pin
530b or plug that can be inserted through both the first and second
cortical bone pieces via an aperture 540b of the combined assembly.
As shown here, the first and second bone pieces can be combined in
a sliding fashion, by slipping the pieces together for example.
Optionally, the first and second bone pieces can be engaged via a
press fit.
As depicted in FIG. 5C, pocket designs for bone graft assemblies
can be configured in any of a variety of shapes and sizes. For
example, as shown here, bone assembly 500c includes a first bone
piece 501c and a second bone piece 502c, each of the bone pieces
including a respective mating feature (503c, 504c). In some cases,
a pocket cross-section can include a curved shape or portion
(510c), a notched shape or portion (520c), or a ridge shape or
portion (530c), or a puzzle shape or portion (540c), or any of a
variety of curved or elliptical shapes or portions (550c). Hence,
male and female assemblies can complement each their respective
shapes. For example, a male mating feature may have a curved shape
that is complementary to a curved shape of a female mating feature.
Similarly, a male mating feature may have a linear shape that is
complementary to a linear shape of a female mating feature. In some
cases, male and female mating features may have shapes with
combined curved and linear portions. It is also understood that in
some cases, a first mating feature may include a combination of
male and female features, and a second mating feature may include a
combination of corresponding female and male features. Often,
interference between mating features can be achieved via size
differential, or a shape differential as described elsewhere
herein.
FIG. 5D depicts an exemplary bone graft assembly 500d according to
embodiments of the present invention. As shown here, the bone graft
assembly includes a first bone piece 510d having a first mating
feature 520d, and a second bone piece 530d having a second mating
feature 540d. The first and second mating features are configured
to provide, when approximated, a hidden engagement zone 550d. The
hidden engagement zone 550d can include, for example, a peripheral
engagement zone 552d, a medial engagement zone 554d, and an inner
engagement zone 556d. In some instances, the first mating feature
520d includes an outer surface 521d, a peripheral surface 522d, a
medial surface 523d, an inner surface 524d, and a core surface
525d. In some instances, the second mating feature 540d includes an
outer surface 541d, a peripheral surface 542d, a medial engagement
surface 543d, an inner surface 544d, and a core surface 545d. The
first and second mating features can be configured to provide, when
approximated, a peripheral engagement zone 522d defined between at
least portions of the peripheral surfaces (522d, 542d) of the first
and second mating features, respectively, a medial engagement zone
554d defined between at least portions of the medial surfaces
(523d, 543d) of the first and second mating features, respectively,
and an inner engagement zone 556d defined between at least portions
of the inner surfaces (524d, 545d) of the first and second mating
features, respectively. The inner engagement zone 556d can be
disposed interior to the medial engagement zone 554d. The medial
engagement zone 554d can be disposed interior to the peripheral
engagement zone 552d. In some case, at least a portion of the
medial engagement zone 554d is disposed between the core surface
525d of the first mating feature and the outer surface 541d of the
second mating feature. As shown here, the first bone piece 510d
includes a first aperture 512d having a diameter or dimension, and
a first core surface 525d defining a diameter or dimension. The
diameter or dimension of the first core surface 525d is greater
than the diameter or the dimension of the first aperture 512d.
Relatedly, the second bone piece 530d includes a second aperture
532d having a diameter or dimension, and a second core surface 545d
defining a diameter or dimension. The diameter or dimension of the
second core surface 545d is greater than the diameter or dimension
of the second aperture 532d. In some instances, the diameters or
dimensions of the first and second core surfaces are the same or
substantially the same. In some instances, the diameters or
dimensions of the first and second apertures are the same or
substantially the same. In some instances, a size differential
between the first aperture and first core surface, and/or between
the second aperture and the second core surface, provide a bone
graft assembly with an inner chamber area 570d.
In some instances, the first and second mating features are
configured to provide, when approximated, a continuous aperture
that extends through the first and second bone pieces of the
assembly. In some instances, the continuous aperture is at least
partially defined by the first and second mating features. In some
instances, the continuous aperture is not at least partially
defined by the first and second mating features. In some instances,
the first mating feature includes an annular wall disposed between
the first mating feature medial and core surfaces, and the second
mating feature includes a second annular wall disposed between the
second mating feature medial and outer surfaces. Optionally, the
second annular wall can be configured to slidingly receive the
first annular wall. In some instances, the first and second mating
features are configured to provide, when approximated, a press fit
at the medial engagement zone.
FIG. 6 illustrates an exemplary multi-piece bone graft assembly 600
according to embodiments of the present invention. Assembly 600
includes a first cortical bone piece 610 having a first mating
feature 612 and an aperture 618, a second cortical bone piece 620
having a second mating feature 622 and an aperture 628, and a
cancellous pin or plug 630 that can be inserted through both the
first and second cortical bone pieces. As shown here, the first
mating feature 612 includes a raised ridge 614 and a pocket 616.
The second mating feature 622 includes a channel 624 configured to
receive ridge 614, and a pin 626. Pocket 616 of first mating
feature is configured to receive pin 626 of second mating feature
(e.g. so as to provide a pivot between the first and second bone
pieces). This embodiment presents a dovetail J-lock design, whereby
the ridge 614 and recess 624 engage as a light press fit, and the
pin 626 and pocket 616 engage as a slip fit. The cancellous plug
630 is inserted through the first and second bone pieces (e.g via
apertures 618, 628), and thereby operates as a lock, so as to
prevent or inhibit the first and second pieces from rotating
relative to each other (e.g. about pivot provided by pin 626 and
pocket 616. In the assembly process, shown here, step 1 includes
placing the pin 626 in the pocket 616 (e.g. so as to provide a
pivot), step 2 includes rotating the bone pieces relative to one
another about the pivot, so that channel 624 receives ridge 614,
and step 3 includes placing the plug 630 in the apertures (618,
628). In some instances, one or both of the bone pieces may include
teeth.
FIG. 7 illustrates an exemplary multi-piece bone graft assembly 700
according to embodiments of the present invention. Assembly 700
includes a first cortical bone piece 710 having a first mating
feature 712, a second cortical bone piece 720 (shown transparently)
having a second mating feature 722. The embodiment depicted here
presents a box dovetail design. The first and second mating
features (712, 722) can engage in a medium press fit. As shown
here, first and second bone pieces can have the same shape, and can
be obtained from a donor bone segment 750 as shown in FIG. 7A. In
this way, cortical walls of the graft assembly can be constructed
by building the walls separately. For example, a graft assembly may
present an open box shape, and include a posterior wall 702, an
anterior wall 704, and two opposing side walls (706, 708). In some
embodiments, each of the walls may be formed of a distinct and
separate piece. A cancellous plug or cancellous material 740 can be
placed within a central portion or area 760 defined by first and
second cortical bone pieces. For example, a cancellous plug or
cancellous material 770 can be placed within one or more open box
shape assemblies as described above.
FIG. 8 illustrates an exemplary multi-piece bone graft assembly 800
according to embodiments of the present invention. Assembly 800
includes a first cortical bone piece 810, a second cortical bone
piece 820, and a third cortical bone piece 830. The cortical bone
pieces can be combined in a stacked configuration, such that the
second bone piece 820 is disposed between the first and third bone
pieces (810, 830). In some embodiments, an assembly may also
include pins or plug. For example, as shown here, assembly 800
includes two or more cortical bone pins 840 and one cancellous bone
plug 850. The pins and plugs are disposed within the first, second,
and third bone pieces (e.g. via respective apertures 860 extending
through pieces of the bone graft assembly). The cortical bone pins
operate to secure the bone pieces together. This design can be used
to stack any desired number of bone pieces together. Optionally,
the central cancellous plug can be configured as a pin.
FIG. 9 illustrates an exemplary multi-piece bone graft assembly 900
according to embodiments of the present invention. Assembly 900
includes a first cortical bone piece 910 having a first mating
feature 912 with multiple bosses or buttons 914, a second cortical
bone piece 920 having a second mating feature 922 with multiple
pockets or recesses 924 configured to receive the bosses. The
bosses can be pressed into the pockets, so as to hold the first and
second graft pieces together. This configuration provides a large
amount of surface area for mating, and the mating feature is
hidden. Further, the pieces can be constructed without removing a
significant amount of graft material. According to some
embodiments, the first and second bone pieces can be provided in a
universal design configuration, wherein the first bone piece has a
combination of bosses and pockets (e.g. two bosses and two
pockets), and the second piece has a combination of bosses and
pockets (e.g. two bosses and two pockets). Hence, in some
instances, two bone pieces, each having the same shape, can be
joined to form a bone graft assembly. In some instances, the bone
pieces can be constructed with a 0.00 (or line to line toolpath)
tolerance press, providing a snap-like fit. The dimensions depicted
here (in millimeters) may be varied or adjusted according to the
use for which the assembly is intended. For example, the dimensions
can be adjusted for appropriate use in a cervical spacer
application, a vertebral spacer application, and the like. In some
instances, assembly 900 may also include a pin or plug 930 (e.g.
that includes cancellous bone material) that extends through
corresponding apertures (940, 950) in the first and second bone
pieces.
Hence, two graft pieces can be joined together by creating a round
female hole on one piece and a corresponding round boss on the
other piece. When the two graft pieces are pressed together, a
uniform interference fit is formed. In some cases, a first graft
piece includes one or more bosses, and a second graft piece
includes one or more corresponding recesses. In some cases, as
described elsewhere herein, the first graft piece can include a
combination of bosses and recesses, and the second graft piece can
include a corresponding combination of recesses and bosses. In this
way, the configuration can present a universal blank or graft
piece, where a single shape can function as both the first piece
and the second piece. In addition to circular or round boss shapes,
graft pieces according to embodiments of the present invention may
be configured to present any desired curved or non-linear boss
shape.
FIG. 10 illustrates an exemplary multi-piece bone graft assembly
1000 according to embodiments of the present invention. Assembly
1000 includes a first cortical bone piece 1010 having a first
mating feature or channel 1012, a second cortical bone piece 1020
having a second mating feature or ridge 1022. The first and second
bone pieces can be engaged by sliding the ridge along the channel,
or by pressing the bone pieces together. First and second bone
pieces can include cortical bone material, for example. In some
cases, the pieces can be joined by a press fit, with a line to line
or 0 tolerance. The configuration shown in FIG. 10 provides a
strong fit. An axial cross-section is also depicted. An exemplary
method of preparing such a bone graft assembly may include cutting
blank profiles, press the blanks together, cutting or adding the
outer and inner profiles or inserter features at the same time or
separately, adding cancellous or other material, and adding surface
ridges or features.
Bone pieces can be created using any desired toolpaths and feed
rates. In some instances, a feed rate can be within a range between
about 10 in/min to about 30 in/min.
In some instances, contraction due to lyophilization may increase
separation resistance in combination with press-fitting. In some
instances, it is possible to machine two graft pieces, and then
heat one piece, and/or cool an adjoining piece, so that there is
less interference when joined, but upon returning to room or body
temperature the interference between the two pieces increases.
Non-Uniform Press Fits
According to some embodiments of the present invention, a mating
feature of a first bone piece can have a shape that is
non-complimentary to a shape of a mating feature of a second bone
piece. Hence, an interface between the first and second mating
features can be defined by a non-uniform press fit. In some cases,
the first mating feature can present a polygon shape, and the
second mating feature can present a curved shape. In some cases,
mating features can present two polygons, e.g. two hexagons, offset
by 45 degrees. In some cases, mating features can present hexagon
and octagon combinations. In some cases, mating features can
present any of a variety of polygons, curved shapes such as ovals,
ellipses, or circles, enclosed splines, irregular amoeba-like
shapes, and the like. In some cases, polygonal shapes may have
rounded corners, which can be formed by rounded endmill tools.
As shown in FIG. 11, the corners or angles 1112 of a square shaped
mating feature 1110 (e.g. boss) can operate as a biting feature,
when pressed together with a round shaped mating feature 1120 (e.g.
pocket). When pressing the bone pieces together, the corners 1112
of the square peg or boss provide a greater press fit than the
other parts of the square peg (e.g. the edges, or sides 1114). Such
configurations provide a firm and sturdy fit that is relatively
easy to press and also difficult to remove. In the embodiment shown
here, the outer diameter 1122 of the round pocket 1120 is
circumscribed about a circle (1122) that is halfway between a first
circle 1130 tangent to the sides of the polygon and a second circle
1140 that intersects the apexes of the polygon. In some cases, the
radial overlap O may be about 0.008 inches. In some instances,
other radial overlap distances O may be used. Hence, as shown here,
the biting edge 1112 can extend into the circle shape to the extent
of the radial overlap O distance. For example, when the first and
second bone pieces are pressed together, a corner segment 1112 of
the boss and an arc segment 1124 of the pocket can be pressed
together.
FIG. 12 presents a related configuration, where the first bone
piece has a first mating feature (e.g. a pine) with a triangle
shape 1210, and the second bone piece has a second mating feature
(e.g. a recess) having a circle shape 1220. In some cases, the
radial overlap O may be about 0.016 inches. In some instances,
other radial overlap distances O may be used. As shown here,
triangle shape 1210 includes biting edges 1212 that more forcefully
impinge against the circle shape 1220 of the second mating feature,
whereas other portions (e.g. 1214) of the triangle shape do not so
forcefully impinge upon the second mating feature, or in some
locations (e.g. 1216) the triangle shape does not radially impinge
against the second mating feature at all. Hence, as shown here, the
biting edge 1212 can extend into the circle shape to the extent of
the radial overlap O distance.
FIG. 13 presents another related configuration, where the first
bone piece has a first mating feature (e.g. a pin) with a pentagon
shape 1310, and the second bone piece has a second mating feature
(e.g. a recess) having a circle shape 1320. In some cases, the
radial overlap may be about 0.005 inches. In some instances, other
radial overlap distances O may be used. As shown here, pentagon
shape 1310 includes biting edges that more forcefully impinge
against the circle shape 1320 of the second mating feature, whereas
other portions of the pentagon shape do not so forcefully impinge
upon the second mating feature, or in some locations the pentagon
shape does not radially impinge against the second mating feature
at all. Hence, as shown here, the biting edge 1312 can extend into
the circle shape to the extent of the radial overlap O
distance.
FIG. 14 presents yet another related configuration, where the first
bone piece has a first mating feature (e.g. pin) with a hexagon
shape 1410, and the second bone piece has a second mating feature
(e.g. recess) having a circle shape 1420. In some cases, the
overlap may be about 0.003 inches. In some instances, other radial
overlap distances O may be used. As shown here, hexagon shape 1410
includes biting edges that more forcefully impinge against the
circle shape 1420 of the second mating feature, whereas other
portions of the hexagon shape do not so forcefully impinge upon the
second mating feature, or in some locations the hexagon shape does
not radially impinge against the second mating feature at all.
Hence, as shown here, the biting edge 1412 can extend into the
circle shape to the extent of the radial overlap O distance.
FIG. 15 presents still a further related configuration, where the
first bone piece has a first mating feature (e.g. pin) with a
heptagon shape 1510, and the second bone piece has a second mating
feature (e.g. recess) having a circle shape 1520. In some cases,
the overlap may be about 0.002 inches. In some instances, other
radial overlap distances O may be used. As shown here, heptagon
shape 1510 includes biting edges that more forcefully impinge
against the circle shape 1520 of the second mating feature, whereas
other portions of the heptagon shape do not so forcefully impinge
upon the second mating feature, or in some locations the heptagon
shape does not radially impinge against the second mating feature
at all. Hence, as shown here, the biting edge 1512 can extend into
the circle shape to the extent of the radial overlap O
distance.
FIG. 16 presents another related configuration, where the first
bone piece has a first mating feature (e.g. pin) with an octagon
shape 1610, and the second bone piece has a second mating feature
(e.g. recess) having a circle shape 1620. In some cases, the
overlap may be about 0.002 inches. In some instances, other radial
overlap distances O may be used. As shown here, octagon shape 1610
includes biting edges that more forcefully impinge against the
circle shape 1620 of the second mating feature, whereas other
portions of the octagon shape do not so forcefully impinge upon the
second mating feature, or in some locations the octagon shape does
not radially impinge against the second mating feature at all.
Hence, as shown here, the biting edge 1612 can extend into the
circle shape to the extent of the radial overlap O distance.
As shown in FIGS. 17A and 17B, a bone graft assembly 1700 can
include a first bone piece 1710 having a first mating feature 1712
and a second bone piece 1720 having a second mating feature 1722.
The first mating feature (e.g. two hex pins and two round pockets)
has a shape that is non-complimentary to the shape of the second
mating feature (e.g. two hex pins and two round pockets). When the
first and second bone pieces are coupled or pressed together, an
interface between the first and second mating features is defined
by a non-uniform press fit. This configuration presents a universal
design, wherein two bone pieces, each having the same shape, can be
joined to form a bone graft assembly. When coupled, the mating
features are hidden. According to some embodiments, the press fit
is relatively easy to establish, although it may be very difficult
to pull apart. The dimensions depicted here (in millimeters) may be
varied or adjusted according to the use for which the assembly is
intended. For example, the dimensions can be adjusted for
appropriate use in a cervical spacer application, a vertebral
spacer application, and the like. In some instances, assembly 900
may also include a pin or plug 930 (e.g. that includes cancellous
bone material) that extends through corresponding apertures (940,
950) in the first and second bone pieces.
Hence, two graft pieces can be joined together by creating a round
female on one piece and a corresponding hexagonal boss on the other
piece. For example, as shown here, first piece include recess 1714
and boss 1716, and second piece includes boss 1726 and recess 1724.
As depicted in FIG. 14, in some cases the hexagonal boss can be
created with an interference fit where the mid-point between the
circumscribed diameter and the inscribed diameter is the same size
as the round hole. When the two graft pieces are pressed together,
a non-uniform interference fit is formed. In some cases, a first
graft piece includes one or more bosses, and a second graft piece
includes one or more corresponding recesses. In some cases, as
depicted in FIGS. 17A and 17B, the first graft piece can include a
combination of bosses and recesses, and the second graft piece can
include a corresponding combination of recesses and bosses. In this
way, the configuration can present a universal blank or graft
piece, where a single shape can function as both the first piece
and the second piece. In addition to hexagonal boss shapes, graft
pieces according to embodiments of the present invention may be
configured to present any desired polygonal boss shape (e.g as
depicted in FIGS. 11-16).
FIGS. 18A and 18B illustrate another bone graft assembly
configurations according to embodiments of the present invention. A
bone graft assembly can include a first bone piece 1810a having a
first mating feature 1812a and a second bone piece (not shown, but
can be similar or identical to first bone piece) having a second
mating feature. As shown here, bone piece 1810a also includes an
aperture or chamber 1830a. The first mating feature (e.g. irregular
hex pin 1814a and race track or canal pocket 1816a) has a shape
that is non-complimentary to the shape of the second mating feature
(e.g. corresponding irregular hex pin and race track or canal
pocket). When the first and second bone pieces are coupled or
pressed together, an interface between the first and second mating
features is defined by a non-uniform press fit. A racetrack shape
can be presented as a rectangle with semi-circular rounded ends. In
addition to the hex pin 1814a shown here, embodiments may
optionally present any of a variety of other polygonal pin shapes
shape (e.g as depicted in FIGS. 11-16).
As depicted in FIG. 18B, a bone graft assembly can include a first
bone piece 1810b having a first mating feature 1812b and a second
bone piece (not shown, but can be similar or identical to first
bone piece) having a second mating feature. The first mating
feature (e.g. irregular hex pin 1814b and race track or canal
pocket 1816b) has a shape that is non-complimentary to the shape of
the second mating feature (e.g. irregular hex pin and race track or
canal pocket). When the first and second bone pieces are coupled or
pressed together, an interface between the first and second mating
features is defined by a non-uniform press fit. A racetrack shape
can be presented as a rectangle with semi-circular rounded ends. In
addition to the hex pin 1814b shown here, embodiments may
optionally present any of a variety of other polygonal pin shapes.
The bone piece of FIG. 18B has rounded edges, as compared to the
bone piece of FIG. 18A which has square edges.
Hence, as shown here, two graft pieces can be joined together in
such a way that an elongated hexagonal boss of a first piece is
pressed into an oval shaped canal of a second piece. In some cases,
the first graft piece can include a combination elongated hexagonal
boss and oval shaped canal, and the second graft piece can include
a corresponding combination oval shaped canal and elongated
hexagonal boss. In this way, the configuration can present a
universal blank or graft piece, where a single shape can function
as both the first piece and the second piece. As shown in FIG. 18A,
the pin mating feature is centrally positioned on the graft
piece.
FIGS. 18C and 18D illustrate how bone pieces (1810c, 1810d) may be
obtained from donor bone graft sites. For example, the bone pieces
can be obtained from a tubular donor bone constructs (1820c, 1820d)
having an inner diameter (I.D.) and an outer diameter (O.D.).
Cleaning and Freeze Drying
Bone graft pieces were soaked in 3% peroxide for approximately 5
hrs, which resulted in normal cleaning effects on the color of the
tissue and no visual effects on the mating feature. Grafts were
individually packaged in 4.times.6 Tyvek and freeze dried. It was
observed that the mating features tolerated the freeze drying
process well, with no noticeable side effects (e.g. cracking by
expansion or separation from shrinkage).
Pull Testing for Pocket and Hex Pin Configurations
Pull testing was performed on 3 samples of each configuration,
using a TT003 apparatus similar to that illustrated in FIG. 19. The
pocket configuration was similar to that illustrated in FIG. 5A,
and the hex pin configuration was similar to that illustrated in
FIG. 17A. The results are shown in FIG. 20.
Additional Pocket Designs, with Window for Cancellous
FIG. 21 illustrates an exemplary multi-piece bone graft assembly
2100 according to embodiments of the present invention. Assembly
2100 includes a first cortical bone piece 2110 having a first
mating feature or boss, and a second cortical bone piece 2120
having a second mating feature or pocket. Optionally, a cancellous
pin or plug that can be inserted through both the first and second
cortical bone pieces (e.g. via apertures 2112 and 2122). As shown
here, the first and second bone pieces engage in such a way that
the mating features are enclosed or hidden from view when the bone
pieces are combined. This configuration provides a large amount of
surface area for mating. Further, the pieces can be constructed
without removing a significant amount of graft material. In some
cases, the bone pieces can be constructed with a line to line
tolerance.
FIG. 22 illustrates an exemplary multi-piece bone graft assembly
2200 according to embodiments of the present invention. Assembly
2200 includes a first cortical bone piece 2210 having a first
mating feature or boss, and a second cortical bone piece 2220
having a second mating feature or pocket. Optionally, a cancellous
pin or plug that can be inserted through both the first and second
cortical bone pieces (e.g. via apertures 2214 and 2224). As shown
here, the first and second bone pieces engage in such a way that
the mating features are enclosed or hidden from view when the bone
pieces are combined. This configuration provides a large amount of
surface area for mating. Further, the pieces can be constructed
without removing a significant amount of graft material. In some
cases, the bone pieces can be constructed with a line to line
tolerance.
FIG. 23 illustrates an exemplary multi-piece bone graft assembly
2300 according to embodiments of the present invention. Assembly
2300 includes a first cortical bone piece 2310 having a first
mating feature or boss, and a second cortical bone piece 2320
having a second mating feature or pocket.
FIG. 24 illustrates an exemplary multi-piece bone graft assembly
2400 according to embodiments of the present invention. Assembly
2400 includes a first cortical bone piece having a first mating
feature or boss, and a second cortical bone piece having a second
mating feature or pocket. Assembly 2400 includes a first cortical
bone piece 2410 having a first mating feature or boss, and a second
cortical bone piece 2420 having a second mating feature or pocket.
Optionally, a cancellous pin or plug that can be inserted through
both the first and second cortical bone pieces (e.g. via apertures
2414 and 2424). As shown here, the first and second bone pieces
engage in such a way that the mating features are enclosed or
hidden from view when the bone pieces are combined. This
configuration provides a large amount of surface area for mating.
Further, the pieces can be constructed without removing a
significant amount of graft material. In some cases, the bone
pieces can be constructed with a line to line tolerance.
FIG. 25 illustrates an exemplary multi-piece bone graft assembly
2500 according to embodiments of the present invention. Assembly
2500 includes a first bone piece 2510 having a mating feature 2512,
a second bone piece 2520 having mating features 2522, 2524, and a
third bone piece 2530 having a mating feature 2532. Here, mating
feature 2512 has a shape (e.g. hexagonal boss) that is
non-complimentary to a shape (e.g. round recess) of mating feature
2522. Similarly, mating feature 2532 has a shape (e.g. hexagonal
boss) that is non-complimentary to a shape (e.g. round recess) of
mating feature 2524. When first and second bone pieces 2510, 2520,
are coupled, an interface between mating features 2512, 2522 is
defined by a non-uniform press fit. Similarly, when second and
third bone pieces 2520, 2530 are coupled, an interface between
mating features 2522, 2532 is defined by a non-uniform press fit.
As shown here, bone graft assembly 2500 includes three stacked bone
pieces. It is understood, however, that by fabricating multiple
bone pieces having appropriate mating features, embodiments of the
present invention encompass bone graft assemblies having any
desired number of stackable pieces.
FIG. 26 illustrates another exemplary multi-piece bone graft
assembly 2600 according to embodiments of the present invention.
The assembly includes multiple bone pieces 2610, each with one or
more mating features. Respective mating features of different bone
pieces have non-complimentary shapes, so that multiple pieces can
be coupled together in a stacked arrangement, and interfaces
between adjacent bone pieces can be defined by non-uniform press
fits. For example, bone piece 2610 may include pegs or bosses 2612
having a hexagonal configuration and recesses or holes 2614 having
circular configurations. As shown here, a bone piece 2610 may
include an aperture or passage 2630.
FIG. 26A illustrates another exemplary multi-piece bone graft
assembly 2600a according to embodiments of the present invention.
The assembly includes multiple bone pieces, each with a mating
feature. Respective mating features of bone pieces 2610a have
non-complimentary shapes (e.g. hexagonal peg 2612a, round hole
2614a) so that individual pieces can be coupled together in a
stacked arrangement and interfaces between adjacent bone pieces can
be defined by non-uniform press fits. As shown here, the graft
assembly can include any number of pieces or layers (e.g. 2+n) as
desired, where n is any integer. As such, the graft assembly can be
considered to include an intermediate or auxiliary bone piece
construct having n pieces. In some instances, the end pieces may
present a flat surface or otherwise be void of any protuberances,
as depicted by the end pieces 2620a and 2630a of assembly
2610a.
FIG. 27 illustrates another exemplary multi-piece bone graft
assembly 2700 according to embodiments of the present invention.
The assembly includes multiple bone pieces (e.g. 2710, 2720), each
with a mating feature. Respective mating features of bone pieces
have non-complimentary shapes, so that individual pieces can be
coupled together in a stacked arrangement (either vertically,
horizontally, or both vertically and horizontally), and interfaces
between adjacent bone pieces can be defined by non-uniform press
fits. For example, bone piece 2720 may include a mating feature
having a hexagonal peg 2722 and a round hole 2724. As shown there,
the mating between two pieces is provide laterally (side to side),
as compared with the top-bottom stacking arrangements of FIGS. 25
and 26, for example.
FIG. 28 illustrates another exemplary multi-piece bone graft
assembly 2800 according to embodiments of the present invention.
The assembly includes multiple bone pieces, each with a mating
feature. Respective mating features of bone pieces have
non-complimentary shapes, so that individual pieces can be coupled
together in a stacked arrangement (either vertically, horizontally,
or both vertically and horizontally), and interfaces between
adjacent bone pieces can be defined by non-uniform press fits. For
example, bone piece 2810 includes a raised boss 2812 on one side of
the piece, and a recessed pocket 2814 on an opposing side of the
piece. As shown here, respective mating features of individual
pieces can be configured to provide, when approximated, a hidden
engagement zone as describe elsewhere herein.
FIG. 29 illustrates another exemplary multi-piece bone graft
assembly 2900 according to embodiments of the present invention.
The assembly includes multiple bone pieces, and individual bone
pieces have one or more mating features. Respective mating features
of bone pieces have non-complimentary shapes, so that individual
pieces can be coupled together in a stacked arrangement (either
vertically, horizontally, or both vertically and horizontally), and
interfaces between adjacent bone pieces can be defined by
non-uniform press fits. As shown here, respective mating features
of individual pieces can be configured to provide, when
approximated, a hidden engagement zone 2902 as describe elsewhere
herein. Using such a buildable and stackable design, it is possible
to create any size and shape of a graft assembly, having any number
of graft pieces. As depicted here, a graft piece may have six
sides, each with a mating feature (e.g. three male mating features
and three female mating features). For example, bone piece 2910
includes bosses 2912a, 2912b, and 2912c, as well as pockets 2914a,
2914b, and 2914c. In related instances, a bone piece may have four
sides, five sides, seven sides, or any other desired number of
sides. The boss and pocket mating features shown in this
configuration may also be provided as hexagonal boss and round
recess interfaces, or as any of the other mating feature designs as
disclosed herein. As shown here, the bone graft assembly includes
an intermediate or auxiliary bone piece construct (e.g. pieces 2,
3, and 5). The intermediate bone piece construct can include a bone
piece pair (e.g. pieces 2 and 3) having a first bone piece (e.g.
piece 2) with a first mating feature and a second bone piece (e.g.
piece 3) with a second mating feature. The first mating feature of
first bone piece of the bone piece pair and the second mating
feature of the second bone piece of the bone piece pair can be
configured to provide, when approximated, a bone piece pair hidden
engagement zone.
An exemplary procedure may involve creating a tissue blank using
custom tooling and a small flat end mill on a CNC (computer
numerically controlled) machine, where the overall shape of the
graft (ID and OD) and the mating features are milled at the same
time with one tool path/operation. The mating feature geometry can
be designed taking into consideration the size and functionality of
the end mill and the CNC. For example, a round endmill can be used
to create a round hole. A bone blank can be milled out of a larger
segment of bone that has previously been examined and supplied.
After the graft piece has been cut, it may naturally fall out of
the larger section of bone, or it may be removed by any other means
desired, without damaging the mating features. After a multiple
number of the individual graft pieces are created, they can be
pressed together, for example manually or by using a vise, to
insure a full and complete press while maintaining the proper
alignment. In some cases, such assembled grafts can be placed into
other vise fixtures for further processing or to complete the
manufacturing of the graft.
In some instances, individual graft pieces can be milled out of
human donated bone, which may be for example femoral and tibial
shafts. Techniques may include using a CNC with a small end mill to
mill out these parts. In this way, it is possible to create a very
precise profile and hold tight tolerances while manufacturing the
mating features. The operator can place the material in a vise and
program or instruct the machine where to start milling. During the
milling session it is possible to program the toolpaths to run at
curtain feed rates and spindle speeds to control the precision of
the graft mating features. After a toolpath is complete, the tissue
blank can be removed from the vise and the remaining shaft of the
bone. During assembly, it is possible to another vise to press
multiple graft pieces together. Many multi-piece graft assemblies
involve a male boss and female recess press fit. In some instances,
a finish surface on a bone can be within a range between 16 G to
500 M finish. Embodiments encompass any of a variety of press fits
and press fit classifications. For example, graft assemblies can be
constructed to provide a press fit of FN1 or a LT1 per ANSI
standard ANSI B4.1-1967 (R1999), incorporated herein by reference.
Exemplary press fits can provide a coupling or fixation between
components of a graft assembly, such that after the components are
pressed together, friction prevents or inhibits them from coming
apart or separating. The friction may be enhanced by compressive
forces present between the coupled components.
Each of the operations described herein may be performed using a
computer or other processor having hardware, software, and/or
firmware, optionally in combination with a CNC or similar bone
processing apparatus. Hence, CNC or other bone processing devices
can be programmed to create the bone graft assembly components as
disclosed herein. The various method steps may be performed by
modules, and the modules may comprise any of a wide variety of
digital and/or analog data processing hardware and/or software
arranged to perform the method steps described herein. The modules
optionally comprising data processing hardware adapted to perform
one or more of these steps by having appropriate machine
programming code associated therewith, the modules for two or more
steps (or portions of two or more steps) being integrated into a
single processor board or separated into different processor boards
in any of a wide variety of integrated and/or distributed
processing architectures. These methods and systems will often
employ a tangible media embodying machine-readable code with
instructions for performing the method steps described above.
Suitable tangible media may comprise a memory (including a volatile
memory and/or a non-volatile memory), a storage media (such as a
magnetic recording on a floppy disk, a hard disk, a tape, or the
like; on an optical memory such as a CD, a CD-R/W, a CD-ROM, a DVD,
or the like; or any other digital or analog storage media), or the
like.
All patents, patent publications, patent applications, journal
articles, books, technical references, and the like discussed in
the instant disclosure are incorporated herein by reference in
their entirety for all purposes.
It is to be understood that the figures and descriptions of the
invention have been simplified to illustrate elements that are
relevant for a clear understanding of the invention. It should be
appreciated that the figures are presented for illustrative
purposes and not as construction drawings. Omitted details and
modifications or alternative embodiments are within the purview of
persons of ordinary skill in the art.
It can be appreciated that, in certain aspects of the invention, a
single component may be replaced by multiple components, and
multiple components may be replaced by a single component, to
provide an element or structure or to perform a given function or
functions. Except where such substitution would not be operative to
practice certain embodiments of the invention, such substitution is
considered within the scope of the invention.
The examples presented herein are intended to illustrate potential
and specific implementations of the invention. It can be
appreciated that the examples are intended primarily for purposes
of illustration of the invention for those skilled in the art.
There may be variations to these diagrams or the operations
described herein without departing from the spirit of the
invention. For instance, in certain cases, method steps or
operations may be performed or executed in differing order, or
operations may be added, deleted or modified.
Different arrangements of the components depicted in the drawings
or described above, as well as components and steps not shown or
described are possible. Similarly, some features and
sub-combinations are useful and may be employed without reference
to other features and sub-combinations. Embodiments of the
invention have been described for illustrative and not restrictive
purposes, and alternative embodiments will become apparent to
readers of this patent. Accordingly, the present invention is not
limited to the embodiments described above or depicted in the
drawings, and various embodiments and modifications can be made
without departing from the scope of the claims below.
* * * * *